Photographic paper



No 1933. P c. SEEL 1,933,824

PHOTOGRAPHIC PAPER Filed July 1931 amnion Paul, & Seal,

Patented Nov. 7, 1933.

1 33.8:4 rno'roommc PAPER Paul C. Seel, Rochester, N, Y., assignor to Eastman Kodak Company, Rochester poration of New York N. Y., a cor- Application July 2, 1931. serial No. 548,293 3 Claims. (01. 95 -8) This invention relates to photographic paper, and particularly to an improvement in a type of paper which is usedfor reversal purposes.

There has been manufactured a photographic paper which has been given such designations as direct positive paper, which is used in the camera for the making of a negative and is then developed and reversed to a positive, the entire process being so arranged that it is possible at low cost and with minimum consumption of time to secure a positive of the object photographed. This type of paper has, for example, been widely used in automatic, machines which are coin controlled, the sitter having delivered to him within a few minutes after posing. a picture of himself. Papers of this kind must be subjected to the ordinary processing baths such as developing, fixing" bleaching, clearing, and rinsing baths and must be delivered dry in the least possible time. Photographic paper made in the ordinary way absorbs so much of these various processing solu-- tions that a relatively long period of washing and drying is required.

It is an object of this invention to provide apaper of the type described which is waterproof and therefore absorbs very little, if any, liquid during the normal treatment. For this reason the paper requires little washing and drying.

My invention is carried out by coating the paper stock, preferably on both sides, with a solution of a polymerized vinyl compound in a suitable solvent. These vinyl compounds which I use are 'for example, polymerized vinyl acetate, or vinyl chloride, or mixtures of the two. These are dissolved in suitable solvents such as acetone, denatured alcohol, butyl alcohol, benzol, toluol, ethyl lactate, ethyl acetate, butyl acetate, or others, or mixtures of any of these.

The following or specific examples of the manner of carrying out the invention.

Example I 10% by weight of polymerized vinyl acetate is dissolved in acetone. This solution is coated on both sides of a paper stock by a suitable coating machine such as is well known in the art; The concentration of the polymerized vinyl acetate may be varied to suit the coating conditions and the thickness of coating desired, Softeners such as tricresyl phosphate or diethyl phthalate may also be included if flexibility of the coated paper is desired.

Example II 10% polymerized vinyl acetate and 4% of tricresyl phosphate are dissolved in a mixture of 59% acetone and 50% toluol. As before, this solution is coated on the paper by means of a coating machine or if preferred it may be sprayed on.

Example III A commercial product now on the market which consists of a mixture of polymerized vinyl acetate and vinyl chloride dissolved in a'solvent may be used for a coating operation such as that de- 5 scribed. The concentration .of the vinyl compound may be varied to suit the coating conditions and the amount of coating required by simply adding solvent to the original solution. This material istusually sold in concentrations varying between 20 and 25% and good coatings can be made by diluting the commercial article with suitable solvents until the resulting solution has a concentration of between 10 and 15% of the vinyl compound. Certain types of coating machines will require concentrations somewhat lower than this.

Coatings of the type I have described will render a normal paper stock practically waterproof. Such a waterproofed stock may then be 0 coated with the usual light-sensitive emulsion of the desired type to provide a finished photographic paper which may be used in any desired manner, but -is particularly suited to the making of direct positives in automatic machines or in any process where rapid processing and drying is necessary. I q

The extent of the penetration of the coating in the paper stock will depend on the properties of the particular materials used, such as whether the paper is of dense or close fibered stock, whether it has been sized, the viscosity of the coating solutions, the length of time during which the paper is in a coating bath, the volatility of the solvents and other like factors.

For purpose of illustration reference is made to the single figure of the drawin in which a piece of paper embodying my invention is shown in section.

InthisfigureJl designates the paper stock hav- 1 0 ing on each surface a layenB of vinyl compound as herein described and a sensitive layer C.

I consider as. included in my invention all modifications and equivalents coming within the scope of the appended claims.

What I claim is:

1. A sensitized photographic p per comprising a paper support, on each side of said support a waterproofing coating containing a polymerized proofing coating a coating of light-sensitive salts 3.1 sensitized photographic paper comprising in a carrier medium. a paper support, on each. side of said support a 2. A sensitized photographic paper comprising waterproofing coating containing polymerized a paper support, on each side of said support a vinyl acetate, and on one side over said waterwaterprooiing coating containing a mixture or proofing coating a coating of light-sensitive salts polymerized vinyl acetate and vinyl chloride, in acarrier medium. and on one side over said waterproofing coating a coating or light-sensitive salts in a carrier medi PAUL (J. SEEL. 

